Seat back



FIG. 1 is a top plan view of a seat back showing my new design;

FIG. 2 is a right side elevational view, the left side being a mirror image thereof;

FIG. 3 is a front elevational view;

FIG. 4 is a rear elevational view;

FIG. 5 is a bottom plan view; and,

FIG. 6 is a front perspective view thereof showing the seat back of the invention on a seat and support outlined in broken lines which do not form a part of the invention. 

The ornamental design for a seat back, as shown and described. 